Mengnan Qu

8-(2-Cycloalkylphenylimino)-5,6,7-trihydro-quinolylnickel halides: polymerizing ethylene to highly branched and lower molecular weight polyethylenes

Cycloalkyl-modified 8-arylimino-5,6,7-trihydroquinolylnickel pre-catalysts, activated with either MAO or Et2AlCl, are highly active for the polymerization of ethylene into branched polyethylene waxes with narrow polydispersity.

Facile Selective and Diverse Fabrication of Superhydrophobic, Superoleophobic-Superhydrophilic and Superamphiphobic Materials from Kaolin

As the starting material, kaolin is selectively and diversely fabricated to the superhydrophobic, superoleophobic-superhydrophilic, and superamphiphobic materials, respectively. The wettability of the kaolin surface can be selectively controlled and regulated to different superwetting states by choosing the corresponding modification reagent. The procedure is facile to operate, and no special technique or equipment is required. In addition, the procedure is cost-effective and time-saving and the obtained super-repellent properties are very stable. The X-ray photoelectron spectroscopy analysis demonstrates different changes of kaolin particles surfaces which are responsible for the different super-repellency. The scanning electron microscopy displays geometric micro- and nanometer structures of the obtained three kinds of super-repellent materials. The results show that kaolin has good applications in many kinds of superwetting materials. The method demonstrated in this paper provides a new strategy for regulating and controlling the wettability of solid surfaces selectively, diversely, and comprehensively.

Targeting polyethylene waxes: 9-(2-cycloalkylphenylimino)-5,6,7,8-tetrahydrocycloheptapyridylnickel halides and their use as catalysts for ethylene polymerization

A series of 9-(2-cycloalkylphenylimino)-5,6,7,8-tetrahydrocycloheptapyridine derivatives (L1–L3) was synthesized, and reacted with nickel halides to form their corresponding nickel complexes (bromide: Ni1–Ni3; chloride: Ni4–Ni6). All organic compounds and nickel complexes were well characterized. The structure of a representative complex Ni1 was determined by a single crystal X-ray study, revealing a distorted trigonal bipyramidal geometry at the nickel centre. Upon activation with either modified methylaluminoxane (MMAO) or diethylaluminium chloride (Et2AlCl), all nickel complexes showed high activities toward ethylene polymerization. The obtained polymers were confirmed to be polyethylene waxes with low molecular weights (in the range of 1.83 to 6.78 kg mol−1) and narrow polydispersity (PDI: 1.38–1.78); moreover, the obtained polyethylenes were highly branched ones. These polyethylene waxes have potential application as functional adducts of lubricants or pour-point depressants.

Bioinspired fabrication of mechanically durable superhydrophobic materials with abrasion-enhanced properties

A novel mechanically durable superhydrophobic material is prepared by a facile method from kaolin. The mechanically durable superhydrophobicity is obtained by mimicking the lotus leafs ability of self-repairing micro-structures and regenerating hydrophobic wax layer. The superhydrophobic property is evaluated by the water contact angle and sliding angle. The mechanical durability is examined by an abrasion test. The superhydrophobicity of the as-prepared material not only is mechanically durable but also can be enhanced by the surface abrasion. The as-prepared superhydrophobic material showed stability in many rigorous environments. The scanning electron microscopy demonstrated that the geometric micro- and nano-structures distributed through the whole material thickness are responsible for this wearable superhydrophobicity.

Fabrication of copper-based ZnO nanopencil arrays with high-efficiency dropwise condensation heat transfer performance

Here, we report a type of copper-based zinc oxide nanopencil array film with high-efficiency dropwise condensation heat transfer (DCHT) performance, which can be obtained by wet-chemistry crystal growth and silane modification. Compared with a hydrophobic flat Cu surface, the nanostructure exhibits a condensate microdrop self-propelling function and maximal ∼140% enhancement in DCHT coefficient.

Fabrication of recyclable superhydrophobic materials with self-cleaning and mechanically durable properties on various substrates by quartz sand and polyvinylchloride

The recyclable superhydrophobic materials are successfully prepared by employing surface-functionalized quartz sand particles embedded into polyvinylchloride. The as-prepared superhydrophobic materials not only exhibited normal superhydrophobicity but also can retain excellent chemical stability and fascinating mechanical durability after many rigorous tests. These materials can pass the 5H pencil hardness test and maintain good superhydrophobicity even after 500 cm abrasion by a mechanical reciprocating abrasion test loaded of 500 g. Importantly, the debris that is scraped from the superhydrophobic materials can be recycled and easily reused to prepare the superhydrophobic materials. This method is suitable for large-scale production because it uses inexpensive and environmentally friendly materials and gets rids of sophisticated equipment, special atmospheres and harsh operation conditions. Its meaningful to a wide range of future applications in industry and real life.

A versatile and efficient method to fabricate recyclable superhydrophobic composites based on brucite and organosilane

AbstractHere we report multifunctional superhydrophobic recyclable materials that have been successfully prepared by surface-functionalized brucite with organosilane on various substrates, such as glass, copper, fibers, sponge, common paper and filter paper. The obtained superhydrophobic materials exhibited water contact angles >150° and water sliding angles <8°. Mechanical durability of the obtained superhydrophobic material was evaluated by a sandpaper abrasion. It was found that once the surface was mechanically damaged, new roughening structures made of the brucite, SiO2 particles and organosilane would expose and still maintain suitable hierarchical roughness, which is favorable for sustainable superhydrophobicity of the material. Additionally, the as-prepared superhydrophobic material has excellent corrosion resistance, high stability and excellent durability as well as self-cleaning ability. Meanwhile, the as-prepared superhydrophobic material is capable of selectively adsorbing oil contamination from water with the separation efficiency larger than 90%. More interestingly, the debris that was scraped from the superhydrophobic materials can be recycled and easily reused to prepare new superhydrophobic materials. The method developed in this work provides a facile, efficient route to fabricate large scale, mechanically stable and durable superhydrophobic materials for a wide range of potential applications.

Facile process for the fabrication of durable superhydrophobic fabric with oil/water separation property

A durable superhydrophobic fabric with oil/water separation property has been successfully prepared by introducing the modified silica nanoparticles and polysiloxane. The as-prepared fabric shows liquid repellency not only to water but also to coffee, milk and tea droplets, which are normal in daily life. Furthermore, the treated fabric shows simultaneous superhydrophobicity and superoleophilicity, which could be utilized as materials to separate oil/water mixture with high efficiency. It is important to note that the obtained fabric kept stable superhydrophobicity even after it suffered severe friction damage. The surface morphologies of untreated/treated fabrics were characterized by the scanning electron microscopy. The chemical compositions were characterized by X-ray photoelectric energy spectroscopy and Fourier transform infrared spectrum. This functionalized fabric will be helpful for developing superhydrophobic and selective oil adsorption materials.